Automatic weight control



June 19, 1928. 1,674,015

E. W. LYNN AUTOMATI C WEIGHT CONTROL Filed May 6, 1927 lll I -F1g. 3; i

Patented June 19, 1928.

1,674,015 UNI-'ren srnrasrni-TENT. @2F-FICE.

EDWARD W; LYNN; OE? DENvEn; COLORADO, asstenioa'v'ro THHOONSOLIDATED STEEL AND mon COMPANY; A 'CORPOEATIONYOE COLORADO.

AUTOMATIC WEIGHT (JONTRL:y

Application mea May. 6, 1927. semaine. 189,349.

This invention relates toimprovementsin` su'rtace'oil the ground and numeral 2 the compensating springl devices for oil well pumps.

Oil wells are, as' asgeneral'rule, muchdeeper than wells for water and are quite f'requently from one thousand to" three or four thousand feet deep. When deeI'Jwells` cease to ilow the oil must be preniovedvbyj Uftentimes the .oil levell will be more ythan a thousand feetbelowthe surface of the ground and lthis longcolumnv means of pumps.

of oil has a great weight andftherefore it requires `a great force to raise the `pump piston and this column of oil. The force required on the up stroke mayrun up` into several tons. On the downfst'roke theweight of the column of oil is sustained by Vthe 'foot valve and therefrethe 'force exerted on 'the lifting apparatus on the dow-n stroke is merely the weight of the sucker "and the sucker rods minus the friction. V

.It `is evident thatunless some device 1s employed for counter-balancing vso as to compensate to some extent at least for the weight of the oil column that the pumpingv engine must be powerful enough to lift the" oil column, the sucker rods, the sucker and to lovercome the-friction.

l t is the object` Ot' this invention'to provide a device consisting of springs which have one end held stationary with respect to the ground and which have their other ends connected with the polish; rod` and which exert a torce tending to raise the polish rod-"with its attached sucker rods and lsucker. VThe strength of these springsmust--be such that they give the maximum assistance to the engine during the operation of the pump.

The above and other-'objects thatmayjbecome apparent as vthis description proceeds' are attained by -Ineans of a combination and an arrangement ofA arts that willfnow describe in detail, an y reference for this pur pose will now be hadrto thev accompanyingv `drawing in which the invention has been illustrated and in which:

Fig. l is a side elevation, partly brokenaway showing my invention applied to an oil-`- well pump;

Fig. '2 is a vertical section 'taken on linery 2-2,Fig;11; i i

Fig. 3 is a toprplan View taken on line 3--3, FigzQ; and

Fig. 4 is a section ltaken `on line l1w-4,

`the drawingnumeral l representsthe outside casingfofthe well,l whiley numeral 3 indicates' the insidecasing ofi the well, which 1s,j usually.' a six-inch casi-ng'. The

pumpfline has been dsignatedfby numeral i een inches to four 'feetff- In the ordinaryf installations the ypumpf isopei'ated by lmeans of an engine which' is vconnected byl a belt Y other pivoted4 at 111.0011@ and of the walking of `Vthe sucker vrods and`sucker Aamountsffto sevealton's whichnnus't' be raised everytimethe purirplA makes an upward stroke. It is evident "that if some `means is provided for counter-balancinglso "as to compensate for en tliecolunin `of 'oi-l iii-pipe 4 'and the weight somefof lthe weight 'that'tis to'be liftedfthat n there will be a great saving in powe`r"'and in the wearand tear of the machinery."

F orttlie'purp'ose of providing a compensating device, the V'l'ollowingfniechanismv has been `pr`oduc'ed.

Two-sec`tions ot casing'- which have been" indicated b'y numeral llhave their"lower-` ends 'e ro'vided with vcaps 17 and are eni`'` bedde" in a concrete block'l8,"so as' to lbe" held invertical-pos'itioinjone'on each side oi 'the pump` linel etil lVhen thesecasing"sections are put into Vpla`ce,`'and 'before the' concrete is pur'ed', tleyar yheld together 'by means Cil of a strap 19, which serves to space them the proper distance apart. In the preferred construction the casing sections lti have an inside diameter ot about ten inches. The caps 17 are provided with a central threaded opening Q0, for the reception of the lower threaded ends E21 ot' the guide bars These guide bars are usually formed ot seven-inch casings and being conccntrically arranged within the casing section 1G. there is an annular space ot' one and one-hall inches between the inner surface ot the casing section and the outer surt'ace of the guide bar. The guide bars extend upwardly substantially to twice the height ot the spacing sections in the manner shown quite clearly in Fig. Q. Surrounding the guide bars are a plurality ot sections ot' helical springs. In the embodiment shown l'our sections ot' springs have been employed. These sections are separated by washers 23. The lower spring section which has been designated b v numeral il; is preferably made from a one-inch steel bar wound with an inch space between adjacent turns and is twenty-tour inches in length. The section directly above has been designated by nu lneral 25 and this is preferably constructed of seven-eighths inch steel and twentytwo inches in length. The third section from the bottom has been designated b v numeral QG and is made from three quarter inch steel and is twenty inches in length. lVhile the upper section which has been designated by numeral 2T is made trom onehaltinch steel and is eighteen inches in length. Slidably connected with the two guide bars 22 is a crosshead, which is made from two identically sha pcd sections 2S which are adapted to he assembled in the manner shown in Figs. 2 and il. Each section QS provided with an opening 2t) which is of such size that it will receive the guide bars Q2 in the manner shown in Fig. These sections are also provided with flanges 30 that are perforated for the reception of clamping bolts 3l. The adjacent surl'aces of the crosshead sections are provided with substantially semi-circular grooves 32, which are adapted to receive the polish bar 5, to which they may be securely clamped by means of the bolts 3l.

From the above description it will be observed that the springs are each composed 0f several sections and that each section is made from a dill'erent size of material. Section 2l is, ol course, a great deal. more powerful than section 25, and section Q7 is the weakest of all because it is made from one-half inch material, whereas the others are all made of larger material. It is evi dent therefore that it a load is applied which tends to compress the spring, that section Q7 will compress a great deal faster than QG and Q6 will be compressed more than section Q5,

while section Q4 will be compressed the least. It is also evident that under the conditions stated, spring section [I will be entirelyY compressed so that the coils will be in con tact with each other before any ot the other sections will be compressed to this extent. We therefore have a spring construction which is unique in this respect that the distance to `which the dillerent sections are compressed is greater ior the upper sections and gradually diminishes towards the hottom of the spring structure. 'l`hisl peculiar construction or the spring results iu an action in which each of the spring sections` will be given a period ol rest during each ot the downward strokes ol the pump. For cxample, when the pump rod o is moved down wardly. spring sections 2T will soon become completely compres. d and will therefore be subjected to no further listortions as longl as the load increases. The spring sections Qt will next be completelyY compressml7 atter which, it thc movement and 'torce is great enough, spring section will he completely compressed. During the upward stroke the actions is reversed and spring sections 2T will remain completely compre .ed until the coils of springl section 2V haviI separated l'rom each other to some extent. This. as above pointed out, gives sections 2T and 2t) a period ot rest during each .stroke which greatly increases their lite and which gives to the spring structure a quickness ot action and a resiliency that. for the purpose l'or which it is used, is superior to what it would be it the spring was made 'l'rom one single piece. There is also another :ul\'anta f fil to be gained by making the springs oli several sections7 namely, that; in case ol' brealt'age itis necessary to replace only the section that is broken. `\\lhercas, il the springs were each made 'from a single piece. the entire spring would have tio be replaced whenever a break occurred.

Il one of the spring sections should brca k it can be readily replaced by unscrewing the bolts 3l suiliciently to permit the crosshead to be moved upwardly on the polish rod. After the crosshead has been moved to a position above the upper ends of the guide bars 22, it may be rotated and thereby make it possible to remove the spring sections by sliding them upwardly over the top of the guide bars. When the broken section has been replaced by a new one, the crosshead is rotated back into position and then moved downwardly so as to put thc springs under the required compression atter which the cross bar is again clamped to the polish bars. f

I want to call attention to the fact that. the connecting rod ll which extends between the upper end ot' the polish rod and the corresponding end of the walking beam is a ridged member so that it can serve to exert Btl tlu

ltltl llt) a downward pressure on the polish rod during the downward stroke of the pump. Since the weight of the column of oil in the pump line is supported on the foot valve the only weight that4 must be supported from the connecting rod 14 during the downward stroke of the pump, is the weight of the polish rod the sucker and the sucker rod minus the resistance due to friction and therefore is much less than the weight that must be raised during the upward stroke. It is evident therefore that it is impossible. to employ springs of suilicient strength to compensate completely for the weights that must be raised on the upward stroke. For, if this were done the force required to conipress Athe springs on the downward stroke would be excessive. The springs must therefore be adjusted to such an extent that the power required to operate the pump becomes the minimum within the limits made necessary by practical considerations of construction.. On theoretical grounds the spring should be adjusted so that the tension in connecting rod 14 during the upward stroke is equal to the compressiondiu'- ing the downward stroke. lVhen adjustments aremade as suggested the power required to operate the pump will be the minimum and the forces required for starting will also be the minimum, thereby reducing the strains on the machinery as well as decreasing the power required to operate the pump.

In order to obtain as easy operation as possible, the annular space between the casings 16 and the guidebars 22 is partially filled with lubricating oil. For the purpose of lubricating the surfaces between the springs and guidebars at points above the tops of the casings, the interior of the guidebars have been filled with sand to a point quite close to their upper ends. In Figure 4 the sand has been indicated by numeral 32 and the heavy oil or grease which is contained within the guidebars 32 has been designated by numeral 83. A plurality of openings 34 have been provided'adjacent the upper ends of the guidebars for the purpose of permitting the grease or heavy oil to seep through to the outside so as to keep the outer surface of the guidebars properly lubricated. v

From the above it will be apparent that I have produced a simple compensating device by means of which the heavy strains to which the pumping machinery would otherwise be subjected can be reduced to a minimum, and which is so constructed that it can be very easily installed and which can be readily repaired in case of breakage.

Having thus described the invention what is claimed as new is: s

1. A weight control device for oil well pumps having a reciprocating polish rod, a guide bar located on each side of the polish rod, the axes ot the guide bars and of the polish rod being parallel, a erosshead slidably connected with the guide bars and clamped to the polish rod, helical springs surrounding each guide bar, said springs being each composed of a plurality of sections.

the several sections of each s rin@ beine* of diierent strength and an annular washerlike member between the ends o' adjacent sections.

2. A compression spring structure coniprising, in combination, a casing, a guide bar located within the casing, said guide bar having an outside dimension which is smaller than the inside diameter of the casing, said guide bar being of greater length than the casing, a helical compression spring surrounding the guide bar and a crosshead slidable on the guide bar.

In testimonywhereof I aix my signature.

EDWARD W. LYNN. 

